水汽吸收线分布于整个中红外波段,它的存在干扰红外光谱的定量分析。分析了水汽谱吸收对测 量精度的影响。利用傅里叶变换红外光谱法分别测量了经过干燥处理的待测气体和未经干燥处理的待 测气体,并分别对两次测量中CO、CO2 、N2 O和CH4 浓度的测量精度及检测限进行了比较。实验表明: 对样气进行干燥预处理可以提高测量精度和检测限。

Absorption of water vapor distributes in the whole mid-infrared bands, and it interferes with the quantitative analysis of infrared spectra. Impact of spectral absorption of water vapor on measurement precision is analyzed. The gas without dryness and after dryness are measured by Fourier transform infrared spectroscopy(FTIR), and the precision and detection limits of CO, CO2 , N2 O and CH4 are compared in the different measurements. The results show that the precision and detection limits were improved after drying of the sample gas.